daedelecs_core/
lib.rs

1extern crate proc_macro;
2extern crate quote;
3extern crate syn;
4
5use proc_macro::TokenStream;
6use quote::quote;
7use syn::parse_macro_input;
8
9#[proc_macro_derive(Component)]
10pub fn component(input: TokenStream) -> TokenStream {
11    // Parse the input tokens directly
12    let ast = syn::parse::<syn::DeriveInput>(input).unwrap();
13
14    // Build the impl
15    let name = &ast.ident;
16    let generated: TokenStream = quote! {
17        impl Component for #name {}
18    }
19        .into();
20
21    // Return the generated impl
22    generated.into()
23}
24#[proc_macro]
25pub fn generate_component_tuple_impls(input: TokenStream) -> TokenStream {
26    let max_size: usize = parse_macro_input!(input as syn::LitInt)
27        .base10_parse()
28        .expect("Failed to parse integer literal");
29
30    let mut impls = Vec::new();
31
32    for i in 0..=max_size {
33        let type_params: Vec<_> = (0..i).map(|j| quote::format_ident!("T{}", j)).collect();
34        let type_constraints = type_params
35            .iter()
36            .map(|t| quote! { #t: Component + 'static });
37
38        let tuple_type = match type_params.len() {
39            0 => quote! { () },
40            1 => {
41                let param = &type_params[0];
42                quote! { #param }
43            }
44            _ => quote! { (#(#type_params),*) }
45        };
46
47        let type_ids_impl = if type_params.is_empty() {
48            quote! {
49                fn type_ids() -> Vec<TypeId> {
50                    vec![]
51                }
52            }
53        } else {
54            let type_ids = type_params.iter().map(|t| {
55                quote! { TypeId::of::<#t>() }
56            });
57            quote! {
58                fn type_ids() -> Vec<TypeId> {
59                    vec![#(#type_ids),*]
60                }
61            }
62        };
63
64        impls.push(quote! {
65            impl<#(#type_constraints),*> SystemData for #tuple_type {
66                #type_ids_impl
67            }
68        });
69    }
70
71    quote! {
72        #(#impls)*
73    }
74        .into()
75}
daedelecs_core/lib.rs

daedelecs_core/
lib.rs
